(1) Field of the Invention
This invention relates to improving the flexibility, abrasion and heat resistance and particularly shear bond (adhesive) characteristics of acrylic polymer Portland cement coating compositions.
(2) Description of the Prior Art:
The prior art is represented by U.S. Pat. No. 4,263,372, which discloses the use of dicyclopentenyl acrylic or methacrylate or a mixture thereof as a hydrophobic binder material in various particulate aggregate systems in conjunction with cementitious materials such as hydraulic cements.
U.S. Pat. No. 4,329,822 discloses a filled polymeric wall facing unit in which a polyester composition such as unsaturated polymerizable polyester resin filled with sand as a suitable filler material and wherein the polymeric composition is applied to a building block which may be of concrete.
U.S. Pat. No. 4,031,282 discloses a similar coating material incorporating a polyester resin or the like for application to improve the esthetic appearance of the object coated.
A number of patents have been issued wherein the use of a polymer in a cement is disclosed. See for example U.S. Pat. Nos. 2,648,645, 3,239,479, 3,937,633, 4,060,425 and 4,211,572.
In U.S. Pat. No. 2,648,645, polyvinyl alcohol in a Portland cement composition is disclosed as being capable of reducing water loss from a slurry.
U.S. Pat. No. 3,937,633 discloses the use of a polymer in a cement slurry for reducing the water loss therefrom.
U.S. Pat. No. 3,239,479 discloses a Portland type cement containing a latex, such as a polymer, in which the composition is intended to retard the setting time of the composition.
U.S. Pat. No. 4,060,425 discloses a Portland cement mixture incorporating a halogen atom with one or more short range strength accelerators such as calcium aluminate and ethylene glycol together with a bituminous emulsion. The patent discloses the substitution of a rubber latex and a resin emulsion for the bituminous material and the result obtained is a rapid hardening cementitious mixture. The product is noted as being useful as a grout which has elastic properties for a slab-type track structure.
U.S. Pat. No. 4,211,572 discloses a dry set mortar in which the water retentive agents such as cellulose ethers are improved by the addition of small amounts of ethylene glycol or the like. The present invention produces a Portland cement coating composition consisting of sand, Portland cement, an acrylic polyer, a defoamer and a critical amount of propylene glycol. The resulting coating material has an unusual and unexpected shear bond characteristic when applied to concrete, wood, hardboard, metal, glass and other materials with unusual and unexpected flexibility along with high abrasion and heat resistance. The addition of a coloring agent to the coating composition such as any of the food coloring agents commercially supplied in an aqueous solution usually incorporating propylene glycol enables the essential propylene gylcol ingredient and the color ingredient to be combined and added to the composition and wherein the color ingredient provides color coding in the mixture when the composition is mixed with water to provide the desired consistency for application to the article being coated, for example a low slump consistency suitable for resurfacing concrete walkways, pavements, and the like, the color coding serving during the mixing process to indicate the presence of a desirable amount of water in the mixture with the color carrying over into the set coating and eventually disappearing.